The invention relates to an arrangement for the damping of torsional vibrations.
In the case of vehicles constructed as convertibles, as a result of the structure and therefore the lower torsional rigidity in comparison to hard top coupes, natural torsional vibrations occur which cause such vibrations and vibrational deflections, particularly in the area of the windshield, that the rear view mirror fastened to the windshield carries out such vibrations making it difficult to view in the rearward direction through the mirror.
In the field of vehicle construction, vibration dampers are known for various applications, thus, for example, on the drive shaft (German Patent Document DE-OS 36 32 418) and on drive units (German Patent Document DE-PS 31 25 830). These dampers are held in elastic bushings which, because of space conditions, may take up an installation space which is necessary for an optimal damping of vibrations.
It is an object of the invention to provide a vibration damper in a convertible which ensures an optimally adapted damping of vibrations to natural torsional frequencies of the vehicle.
According to the invention, this object is achieved by providing an arrangement for the damping of body-side torsional vibrations on a convertible, comprising a damper held elastically by way of elastic slide bearings on a frame of a windshield and arranged at a distance from the frame so that it can relatively freely swing in the transverse direction of the vehicle, the slide bearings each having a maximal height damping the natural torsional frequency of the vehicle in the are of the frame.
The principal advantages achieved by the invention are that the vibrations on the frame of the windshield can be reduced by way of a metallic mass damper to such an extent that an unimpaired rear view is permitted through the mirror fastened to the windshield or to the frame. In addition, the remaining vibrational behavior is markedly improved particularly in the area of the dashboard with the steering wheel.
Depending on the construction of the vehicle or of the windshield frame, the damper is held inside this frame between connected profiled struts or outside the frame elastically by way of bearings. The damper is fastened to the upper frame of the windshield and, because of the very crowded space conditions, for the optimal damping of the vibrations, elastic slide bearings are required that have a height which corresponds approximately to the height of the damper or of the clearance height of the connected profiled struts.
The elastic bearings are preferably arranged on the two free ends of the damper mass and are connected with their one lower end to a profiled strut and with their other upper end with the mass of the damper so that an optimal length of the elastomer body can be achieved. By means of this arrangement of the bearing, a bearing is advantageously achieved which is statically acted upon by pressure and which has a favorable effect with respect to fatigue strength for the damping of natural torsional frequencies in the area of the windshield frame.
On each free end, the damper mass may also be encompassed by a holder, the projecting leg of which is connected with the elastomer body of the bearing and which is connected with a bracket which has lateral longitudinal stops and front-side transverse stops.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.